In general, to detect a pulse electric current, a large alternating electric current or the like, shunt resistance type current sensors are proposed in which an electric current to be measured is supplied to a shunt resistance portion having a known resistance value and a voltage drop generated in the shunt resistance portion is detected, thereby detecting a magnitude of the electric current to be measured. In the shunt resistance type current sensors, because the resistance value of the shunt resistance portion is changed depending on a temperature thereof, the temperature of the shunt resistance portion is detected and then the resistance value is corrected based on the temperature. For this reason, a temperature sensor, together with a voltage detection IC for detecting a voltage drop to detect a magnitude of an electric current to be measured, is mounted on a circuit board.
For example, according to PTL 1, a bus bar connected to a negative terminal of a battery also serves as a shunt resistance portion for detecting a magnitude of an electric current of the battery. In this case, the bus bar and a circuit board are electrically connected to each other by two poles for detecting a potential difference caused by the shunt resistance portion, and a temperature sensor is disposed on a portion of the circuit board adjacent to one pole.